Perhaps you should try some spelling variations:
hieu van » thien van, lieu va, hieu ve
van hanh » van thanh, ban hanh, van ban
te sach » toc sach
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
cao duc » dao duc, cao suc, giao duc
van anh » van thanh, tuan anh, van minh
cua tre » cua te, cuu tre, cua triet
va cua » va chua, via cua, ca cua
x hoi » xa hoi, o hoi, x ho

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ky nang x hoi. ((hieu van) or (hieu va)) cao duc ((van hanh) OR (van anh)) va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky nang x hoi. ((hieu van) OR (hieu va)) cao duc ((van hanh) OR (van anh)) va cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky nang x hoi. ((hieu van) or (hieu va)) cao duc ((van hanh) OR (van anh)) va cua tre".
• Adding a wildcard symbol may retrieve word variants: te sach ky nang x hoi. ((hieu van) or (hieu va)) cao duc ((van hanh) OR (van anh)) va cua tre*.